| 摘要 |
A method of measuring a capacitance (C) of a sensor having a working electrode that is coated by an insulating layer and a ligand forming an affinity surface. The method involves the steps of bringing the electrode into contact with an analyte, supplying a constant first current (I1), and a constant second current (I2) of opposite direction to the first current (I1), and a constant third current (I3) of same direction as the first current (I1) during determined time periods to the sensor. Further the method includes sampling the potential (V) built up across the sensor, and calculating the capacitance of the sensor from the inclination (B, D, F, H) of a potential curve received in response to the current supply. A method used for detection of an interaction between a ligand and an analyte is also disclosed. |
| 主权项 |
1. A method of measuring a capacitance (C) of a sensor having the capacitance and a resistance, the sensor including a working electrode that is coated by an insulating layer with a ligand arranged thereto forming an affinity surface on said electrode, the method comprising the steps of:
bringing said electrode into contact with an analyte; supplying a constant first current (I1) to the sensor during a first time period (t1) by means of a current source until a potential built up across the sensor has reached a predetermined value (V), and simultaneously sampling the potential (V) built up across the sensor; supplying a constant second current (I2) to the sensor during a second time period (t2) by means of the current source, the second current (I2) having an opposite direction compared to the first current (I1) and having a same absolute value as the first current (I1), wherein the second time period (t2) is equal to said first time period (t1) or is equal to said first time period (t1) multiplied with a factor two, and simultaneously sampling the potential (V) built up across the sensor; supplying a constant third current (I3) to the sensor during a third time period (t3) by means of the current source, the third current (I3) having the same direction as the first current (I1) and having the same absolute value as the first current (I1), wherein if said second time period (t2) is equal to said first time period (t1), the third time period (t3) is zero, and if said second time period (t2) is equal to said first time period (t1) multiplied with a factor two, the third time period (t3) is equal to said first time period (t1), and
simultaneously sampling the potential (V) built up across the sensor; andcalculating the capacitance (C) of the sensor by means of an inclination (B, D, F, H) of a potential curve received by the potential (V) built up across the sensor in response to the supply of the constant currents (I1, I2, I3), if said potential (V) has returned to zero when a cycle including said time periods (t1, t2, t3) has lapsed. |
